Hi!
That's so great that you're going to Convention! I've always wanted to go, maybe next year. I fly through Memphis ALL the time, NW is the only airline that flies into my hometown. So, whenever we want to get out of town, we have to connect through Memphis. It's one of the easily navigable large airports I've been to. There are lots of on-screen flight information monitors, the concourses are labeled alphabetically, and there are lots of helpful people there.
I've not had to show my ID at Memphis (last time I was there was last month, so I doubt things have changed too much), but it's nice to keep with your tickets just in case. The security checkpoints aren't too intense...wearing pants w/o rivets or zippers, and a bra w/o metal would probably save you some time.
Bring a book! Memphis has a Cinnabon counter in the middle of a concourse...yum!